Pre-filled syringes and pre-filled vials and the like in which pharmaceutical products are filled in advance are manufactured for convenience at medical sites. A work of filing the pharmaceutical products in these syringes and vials is performed in a filling work room under an aseptic environment (hereinafter, referred to as an “aseptic processing room”). Each of the syringes and vials used for this work are small, and required quantities to be processed are large. Thus, these syringes and vials are sterilized by Gamma-ray irradiation, electron beam irradiation, EOG (ethylene oxide gas) and the like in respective manufacture stages and conveyed in a state grouped into predetermined numbers and accommodated in packages into the aseptic processing room.
The packages include a medical drug containers package (P in FIG. 1) proposed in the following Patent Literature 1 or described as a prior art, for example. These packages are generally called peel-open packages and include a plastic tab (P1 in FIG. 1) formed in conformity to a shape of an article such as a syringe or a vial accommodated therein and an upper-surface seal (P2 in FIG. 1) with air permeability. For this upper-surface seal, an unwoven cloth made of polyethylene microfibers with high density or Tyvek (trademark) is used in general, the air can permeate into the plastic tab through micropores in this Tyvek (trademark), but intrusion of microorganisms is prevented.
The package constituted as above has its outsides further packed by a packing bag and distributed/transported. However, in distribution or transportation or when the package is taken out of the packing bag to be conveyed into the aseptic processing room, the outer surfaces of the plastic tab and the upper-surface seal are contaminated. Therefore, without sterilization of the contaminated outer surfaces, they cannot be conveyed into the aseptic processing room. Thus, after the outer surfaces of the plastic tab and the upper-surface seal are sterilized by a sterilizing device provided continuously to the aseptic processing room, conveyed to the aseptic processing room, the upper-surface seal is peeled-open from the plastic tab in the aseptic processing room, and the filling work is performed to the sterilized syringes and vials inside.
For these sterilizing devices, various methods such as EOG (ethylene oxide gas), hydrogen peroxide gas, ozone gas, plasma, Gamma-ray irradiation, ultraviolet-ray irradiation, electron beam irradiation and the like are employed in accordance with the purpose. One of the most common methods is a method by a hydrogen peroxide gas.
In the method by the hydrogen peroxide gas, a required level of sterilization effect can be obtained, but it requires some processing time for sterilizing the entire package and if the hydrogen peroxide gas enters the inside of the plastic tab through the upper-surface seal made of Tyvek (trademark), removal of the hydrogen peroxide condensed inside requires time, which is a problem.
Thus, in a sterilizing device requiring processing of a large number of articles per unit time as in manufacture of the pre-filled syringes, a method with high sterilization effect in short-time processing is in demand. Thus, in Non-Patent Literature 1 below introduces a sterilizing device which can obtain higher sterilization effect than that in a common device using a hydrogen peroxide gas or the like and moreover, incorporates low-energy electron accelerator as a safe device with high productivity and no remaining substances.
This sterilizing device is actually operated in processing of the packages accommodating the pre-filled syringes, and the package accommodating the syringes subjected to sterilization processing in advance has its outer surface sterilized by an electron beam and then, conveyed to the aseptic processing room by a conveyer. This device projects electron beams to all the surfaces of the package from each of irradiation windows (56A, 57A, 58A) in three directions by three units of low-energy electron accelerators (56, 57, and 58 in FIG. 2) disposed by an angle of 120 degrees, respectively.
It is to be noted that, in this device, by controlling a dose of the electron beam to be projected, the plastic tab and the upper-surface seal can be efficiently sterilized. According to the Non-Patent Document 1 below, as many as 3600 syringes per hour can be processed by this device, whereby high productivity is realized.